Power Amplifier Pentode
Groove Tube ~ Rating 4
This is for One Tube in the Box.
Groove Tubes use a 10-point scale (10 being
the highest output ); “medium” tubes fall in the 3-7
range and are most similar to stock tubes for many
amplifiers, especially Fender®.
For amp service techs or those wishing to customize
amplifiers to achieve specialized tone, “high” (8-10)
and “low” (1-2) tube sets are available. In most cases,
these may require amp re-biasing by a qualified service
The Groove Tube GT5881C Vacuum tube is a glass-octal type
used in the output stage of audio
amplifying equipment, especially units designed to
have ample reserve of power-delivering ability. It requires
an octal socket. This tube, like other power-handling
tubes, should be adequately ventilated.
Heater for Unpotential Cathode:
AC or DC Voltage ............. 6.3 Volts
AC or DC Current ............. 0.9 Amps
Preferred Substitutions .......... 6L6S, 6L6B,
6L6WXT, 5881, 6L6, 6L6G, 6L6GB, 6L6GC,